Hydraulic lifting jack



Oct. 17, 1950 J. N. M LEAN HYDRAULIC LIFTING JACK 2 Sheets-Sheet 1 Filed July 25, 1947 $1. w lfi /4 TTOR/VEYS.

Oct. 17, 1950 J. N. M LEAN HYDRAULIC LIFTING JACK 2 Sheets-Sheet 2 Filed July 25, 1947 INVZNTOR. W ATTORNEYS.

' Patented Oct. 17, 1950 HYDRAULIC LIFTING JACK James N; McLean, Buffalo, N. Y., ass'ignor to .Chapman Transmission Corporation, Buffalo,

N. Y., a corporation of New York Application July 25, 1947, Serial No; 763,475

1 Claim. -(Cl. 254-93) This invention relates to a hydraulic lifting jack which'is more particularly intended for engaging different parts of an automobile for raising the same while it is serviced, but the same is also capable of lifting other kinds of loads.

It is the object of this invention to provide a lifting jack of this character which. is very light,

compact and strong so that the same can be readily carried around as part of the tool equipment of a, car and which can also be very easily and quickly operated for raising and lowering i the load which is imposed on the same and thus facilitate and render more convenient the operation of servicing a car or similar work.

In the accompanying drawings: Fig. l is a vertical longitudinal section ofa hydraulic lifting jack embodying this invention and showing the same in a lower or inoperative position. r

Fig. 2 is a side elevation of the same.

Fig. 3 is a horizontal section, on an enlargedv scale, taken approximately on line 33,Fig. 2'.

Figs. 4, 5 and 6 are vertical sections taken on the correspondingly numbered lines in Fig. 3.

Fig. '7 is a horizontal section, taken on line 1'l, Fig. 1.1 I

Fig. 8 is a horizontal section on an enlarged scale, taken on line 88, Fig. l.

In the following description similar characters of reference indicate like parts in the several figures of the drawings.

In general, thisliftingjack comprises support. ing means for supporting the same on the floor or ground, a hydraulic lifting device mounted on the supporting means, bearing means which are adapted to engage the load to be lifted and which are actuated by the lifting means, pumping means for producing a, hydraulic pressure on the lifting means, and valve devices which control the movement of the lifting liquid to the lifting means and the return of the same therefrom to storage,

means.

The supporting means may-bevariously c011 structed but in their preferred form the same include a base'whichis preferably constructed from a sheet of metal stamped into dish-shaped form to provide a. downwardly flaring disk Hi the outer marginal lower edge ll of which is adapted to rest upon the floor or ground and the central ele-v vated part of which is provided with an opening l2. Upon this disk is arranged a cup-shaped bearing of metal which has a vertical cylindrical.

body l3 arranged in the opening of the base disk and provided at its upper end with a laterally projecting collar I4 resting on the upper side of the base disk while its lower end is provided with an inwardly turned annular flange H) which tapers downwardly. This bearing cup is preferably secured to the base disk by welding the body of the same. to the underside of the base disk, as

shown at 16 in Figs. 1 and 4.

The hydraulic lifting device which is mounted. on this supporting base comprises an upright tu;

bular lifting chamber or body ll of cylindrical form, a lower head l8 applied to the lower end of this body and an upper head l9 applied to the.

upper end of this body. The connection between the lower head l8 and the lower end of the lift- 7 ing cylinder is preferably effected by forming an. I externally screw threaded neck 26 on the lower: end of the cylinder ll and screwing the same into an internally threaded socket 2! on the upperside of the lower head 58. A leaktight joint is fo-rmedbetween this lower head and the lifting cylinder by means which preferably consist of a soft washer 22 interposed between an upwardly facing shoulder 23 on the head it. and a down wardly facing shoulder 2 3 on the exterior of the cylinder H, as shown in Figs. 1 and 4 The.

upper cylinderhead i9 is preferably secured to the upper end ofthe cylindrical body ll by means of an externally threaded neck 25 arranged at the upper end of this body and engaging with an internally threaded socket 26 on the underside of the respective head. i

The numeral 21 represents a piston arranged within the lifting cylinder or chamber Gland movable vertically therein, a liquid tight joint be-' ing formed between these two members by means of an elastic packing ring 28 arranged in an an-:.;

nular groove on the piston and engaging with the bore of the cylinder ll a'zsshown in Fig. l.

The upper side of this piston is connectedwith. the lower end of a piston rod.29 which has its lower part arranged within the upper part of the lifting cylinder while its upper part is arranged, above this cylinder and its intermediate part slides vertically through an opening in the upper A leaktight joint is formed" cylinder head l9. between this upper cylinder head and the'piston rod by means of a packing'disk or ring 36 resting on the bottom of a socket 3! in the upper. side of' the upper cylinder head and a tubular gland 32 which is screwedinto this socket and adapted to bear against the upper side of this packing so that the latter engages tightl with the periphery of the piston rod.

In using this lifting jack the cylinder and parts mounted thereon may tend to incline this cylinder at different angles with reference to the;

ale

3 vertical rod for adapting the lifting jack to the position of the load and in order to permit the lifting cylinder to thus change its angular posi tion automatically while being used means are provided which enable the lower head of the cylinder to rock laterally on the base to the requisite extent. The preferred means for accomplishing this purpose comprise a vertical stem 33 which projects downwardly from the underside of the lower cylinder head into the bearing cup l3 and engages its rounded lower end with the upper side of the bearing flange l5 of this cup, and a metal coupling ring as engaging its inner side with an annular groove 35 on this stem while its outer side bears against the bore of the cup, as shown in Figs. 1 and l. By these means the lifting cylinder is capable of rocking or swiveling on the base in order to adapt the jack to the position of the load which is being lifted. The ring 34 is split, as shown in Fig. 8, so as to permit of applying the same to the stem and also frictionally engaging with the cup [3 so that these parts remain in an assembled position while the lifting jack is ready for use, as shown in Figs. 1 and 4. When the lifting jack is not in use the stem 33 may be Withdrawn from the bearing cup of the base in order to permit these parts to b packed more closely for storage purposes.

Raising and lowering of the piston 27 in the cylinder [1 while using the hydraulic jack is effected by admitting a liquid, such as oil, under pressure into the lower part of this cylinder for the purpose of raising the piston and the parts connected therewith and upon permitting the liquid to escape from this cylinder so that the piston and its load can move downwardly by gravity. The liquid for this purpose is taken from a storage chamber or reservoir 35 and delivered to the lower end of the lifting cylinder and returned from the latter to the storage chamber. This chamber has a body or wall 31 of cylindrical shape which surrounds the lifting cylinder l! but is separated therefrom and has its upper and lower ends secured to-the opposing sides of the lower and upper cylinder heads I8, l'9 by welding, as shown in Fig. 1 or by other suitable means. It will be noted that the heads [8, l9 form the closures of both the lifting chamber and the storage chamber at the lower and upper ends thereof.

During the operation of the lifting jack the piston is moved vertically in the hydraulic lifting cylinder together with the load by supporting means which are preferably constructed as follows:

The numeral 38 represents a lifting head which is preferably secured to the upper end of the piston rod by means of a pin 39. From this lifting head a. lifting or guide sleeve 439 projects downwardly and engages the periphery of the reservoir wall with a sufficiently tight fit to permit this sleeve to slide vertically on this wall but prevent any lateral movement relative thereto.

If desired the upper lifting head 38 of the piston rod may be engaged directly with the load which is to be lifted in the position of this head relative to the load permits of such use. In order, however, to permit of varying the place of engagement of the lifting jack to suit the position of the load adjustable engaging means are prcvided which are preferably constructed as follows:

The numeral 4! represents a. lifting hook or arm which is arranged at the side of the guide sleeve 40 and adapted to engage the desired part of an automobile or other load which is to be lifted. This lifting hook projects laterally from a collar 42 which surrounds the guide sleeve 4t and is secured thereto so as to be adjustable lengthwise thereon. The means for effecting this adjustment preferably consist of two clamping lugs 43 which are arranged on this sleeve on opposite sides of a longitudinal slit M therein and a clamping bolt 45 having its threaded end engaging a threaded opening in one of the lugs 43 while its head 46 engages the outer side of the companion clamping lug. Upon loosening the bolt 45 the collar 42 and hook may be adjusted vertically on the guide sleeve to the desired position for engaging the hook with the load and thereafter tightening of this bolt will securely hold this hook in position on the guide sleeve. To facilitate turning of the clamping bolt its head is provided with a cross pin 41 which may be grasped firmly by the hand when adjustment is desired.

The liquid used in this lifting jack is introduced into the storage chamber or reservoir through the filling opening 48 which is preferably formed in the lower head of the lifting cylinder so as to extend from the exterior of this head to the interior of this chamber, which opening is closed by means of a screw plug 49, as shown in Figs. 3 and 4 or by any other suitable closure means, after the reservoir has been filled.

The valve means whereby the pressure liquid is conducted from the storage reservoir 36 to the lower end of the lifting chamber or cylinder for effecting a lifting operation and thereafter returned from this, cylinder to the reservoir for permitting the lifting piston to again descend are constructed as follows:

Within the lower head ill of the lifting cylinder a passage is formed whereby the pressure liquid is conducted from the lower part of the liquid reservoir to the lower part of the lifting cylinder which passage includes a supply section 50 having its inlet end opening into an annular pocket 5! on the lower cylinder head which communicates with the lower end of the storage chamber, a discharge section 52 opening into the lower end of the lifting cylinder and an intermediate transfer section 53 connecting the supply section 5!] with the discharge section 52, as shown in Figs. 3, 4, 5 and 6. Between the supply passage section and. the transfer passage section this liquid pressure passage is provided with a supply valve seat 54, and between this transfer section and the discharge section of the pressure passage the same is provided with a discharge seat 55 of somewhat longer diameter than the supply valve seat, both of these valve seats facing in the direction in which the liquid flows or passes from the storage reservoir 36 to the lifting cylinder if. The supply valve seat is adapted to be engaged and disengaged by a supply check valve 56, preferably of ball form, and the discharge valve seat is adapted to be engaged by a discharge check valve 5'! preferably of larger diameter than the supply check valve and also of spherical or ball form. These two valves are yieldingly held in their closed position and in engagement with their respective seats by a light spring 58 arranged in the transfer section 53 and bearing at its opposite ends against the supply check valve 56 and the discharge check valve 51, and a oomparatively heavy spring 59 arranged in a part of the discharge section 52 and bearing at one end against the discharge check valve 5'5 and at its opposite end against a screw plug 60 which closes a part of the discharge passage section 52 terior of the head i8 but is normally closed by retaining plug 50, as shown in Figs. 3 and 5.

During the lifting operation of this jack a suction-and a pressure effect are alternatel produced in the transfer'passage section 53 so that the supplyand discharge check valves are alternately opened and closed and cause'lifting or pressure liquid to be drawn from the storage reservoir into the transfer section 53 and then delivered from the latter into the lifting cylinder for causing the piston 21 to be raised and lift the load which is imposed thereon.

For the purpose of causing the lifting or pressure liquid to operate in this manner pumping means are provided which are manually operated and are preferably constructed as follows:

iii represents an upright pump barrel or cylinder formed in the upper part of the lower cylinder head I8 and opening at its lower end into the transfer section 53 of the pressure passage, as shown inFig. 5. Within this pump barrel is arranged a vertical reciprocating pump plunger 62 which extends to the exterior of this head on the upper side thereof and is reciprocated by a manually operated lever arranged above the adjacent part of this head. A liquid tight joint is formed between this plunger and the pump barrel by a packing ring or gasket 53 arranged around the upper part of this plunger and rest ing on the bottom of an internally screw threaded pocket 64 in this head, and a tubular gland 65 screwed into this pocket and bearing against the upper side of this packing ring so as to press the same tightly against the periphery of this plunger.

The operating lever preferably comprises an inner section 65 which is constructed in the form of a fork and an outer section 6'! which is constructed in the form of a tube and is removably connected with the inner section by engaging one end of this tube with a socket 68 on the inner lever section, as shown in Fig. 5. The inner section of this operating lever straddles an upwardly projecting bracket 59 on the adjacent part of the lower head l8 of the pressure cylinder and is pivoted thereto by means of a horizontal coupling. pin it. Coupling means are provided for connecting the inner section of the operating lever with the pump plunger so as to permit this lever to swing vertically about the axis of the pin HI and still enable the pump plunger to move in a rectilinear direction in the pump barrel. In the preferred construction of these coupling means the same comprise a yoke or clip having an upper horizontal bar ll extending over the outer end of the plunger and two inwardly turned jaws 0r hooks 12 arranged at opposite ends of the bar TI and engaging with opposite sides of an annular groove 13 formed circumferentially on the periphery of the pump plunger at the outer end thereof. This yoke is arranged between the arms of the forked shaped inner section of the operating lever and its cross bar H is spaced from the outer end Of the plunger 62 so as to form a horizontal slot 14 between these members which receives the central part of a coupling pin 15 having its opposite ends mounted on the adjacent parts of the arms of the inner secand the load imposed section 16 of this return 6 tion 66 of the operating lever. Upon actuating the operating lever the same swings vertically about the pivot pin 10 on the bracket '69 and the coupling pin 15 slides horizontally in the slot HI between the yoke and the plunger. i

When the lifting jack is not in use the tubular outer-handle section Bl of the operating lever may be removed therefrom and storedcompactly' with the otherparts of this apparatus;

As the plunger 21 is raised by the operating lever, pressure liquid is drawn from the storage reservoir 36 through the supply passage and into the transfer passage during which time the supply check valve 56 is moved into an open position but the discharge check valve 51 is held shut. During the downward stroke of the pump plunger the liquid drawn into the pump barrel and the transfer passage is expelled therefrom through the discharge passage 52 into the lower end "or the lifting cylinder or chamber [1 during which time the pressure on the liquid together with the presure of the spring 58 operates to close the supply check valve 56 but the discharge check valve 5'! .is pushed into an open position against the resistance of the heavier spring 59.

Inasmuch as the closing of the supply check valve is effected by the combined pressure of the spring 58 and the downward stroke of the pump plunger this spring can be made comparatively light but to insure closing of the discharge valve, notwithstanding the forward pressure of the light spring 58 against the same, the closing spring 59 of the discharge valve is made comparatively heavy. By these means a comparatively simple construction of valve mechanism is provided for controlling the flow of pressure liquid from the reservoir and pump to the lifting cylinder and yet obtain a. reliable operation of the same.

After a sufficient quantity of liquid has been transferred from the storage reservoir to the lifting cylinder to elevate the piston in the latter thereon to the desired height, oscillation of the operating lever is dls-v continued and the load is retained in its elevated position by the retention of the pressure liquid in the lifting cylinder and the passages connected therewith by the discharge check valve 51 which at this time is in a closed position. When it is desired to again lower the load which has been elevated by the lifting jack the pressure liquid is released and permitted to flow back from the lifting cylinder into the storage chamber or reservoir by manually operated releasing means which are preferably constructed as follows:

The numerals 16, H represent the receiving and delivery sections of a liquid return passage and 18 a valve seat which is formed in this passage between these two sections and faces in a direction opposite to the flow of the stream of liquid .as it escapes from the pressure or lifting cylinder to the storage reservoir. The receiving passage preferably open into a part of the discharge section 52 of the pressure passage and the delivery section 11 of this return passage preferably opens into the enlargement 5! in the lower head 18 of the pressure cylinder and storage chamber, both of these sections l6, ll being formed in this head, as shown in Figs. 3, 4 and 6.

The numeral 19. represents a releasing valve,

preferably of ball shape, which is movable to ward and from the releasing valve seat 18 for the purpose of closing or opening the releasing passage.

This valve is tightly held in its closed position while the lifting pump is operated so that only pressure liquid can flow from the storage chamber 35 into the lifting cylinder ll during the lift ing operation of the jack. For this purpose the releasing valve is held against its seat '58 by means of a retaining pin 85) which is adapted to bear with its inner end against the ball valve 19 opposite to its seat but may be retracted therefrom when it is desired to release this valve and permit a return flow of the pressure liquid from the lifting cylinder ll to the storage chamber or reservoir 35. For causing this retaining pin-tooperate in this manner the same is mounted on the inner end of an externally threaded screw 8i which works in a threaded screw sleeve 82 as shown in Fig. 6. This screw sleeve in turn is, screwed into an internally threaded opening 98 forming part of the return passage section 11 in the head 18 and bears at its inner end against a soft washer 83 which rests against a shoulder 84 on the head :8 and causes this washer to be pressed against the periphery of the retaining pin 8f! so as to form a liquid tight joint therewith. Rotation of the screw HI and the movement of the retaining pin toward and from the releasing valve is effected b means of a head 85 arranged at the outer end of the screw 8! and provided with a cross pin 86. This screw may be turned for either opening or closing the releasing valve 19 by grasping its head 85 and pin 86 by the hand but if desired this screw may be operated more effectively by providing the outer end of the tubular handle 6? with transverse notches 8'! whereby this end of the handle is converted into the shape of a forked wrench and permits of slipping the tubular handle over the head 85 of the screw and also engaging the notches 81 of the same with the cross pin 86, as shown in Fig. 6. In order to make it unnecessary for the operator to stoop while operating the releasing screw 8; and retaining pin the axis of this screw and the parts associated therewith may be inclined so that the outer end of this screw is elevated rel-- ative to the inner end thereof, as shown in Figs. 2 and 6.

Upon retracting the retaining pin 8&3 from the return valve 19 the latter is opened automatically by the pressure of the fluid in the lifting cylinder and thus permits this liquid to flow from this cylinder backwardly'through a part of the discharge section 52 of the pressure passage then successively through the receiving and delivery sections ll of the return passage and back into the storage reservoir 35 preparatory to b ing again used during another lifting operation of the jack. After the lifting piston has descended in the lifting cylinder the releasing valve 19 is again pressed against its seat by means of the pin 31} and screw 8i, thereby closing the return passage and placing the lifting jack. in conditionfor performing another lifting operation.

If desired the handle 61 of the operating lever, when detached from the inner section 6% of the same may be slipped over one end of the pin 4'! on the clamping screw as, as shown by dotted lines in Fig. 2, and thereby enable this screw to be tightened more effectively for holding the lifting hook ii and its collar 42 against slipping on the guide sleeve 40 during the operation of lifting a load.

Adjacent to its upper end the lifting cylinder 11 is provided with a relief opening 38 extending from the bore thereof to its periphery and thereby place the interior of this cylinder in communication with the storage reservoir adjacent to the upper ends of the same as shown in Fig. 1. This relief opening is so located than when the lifting piston is arranged below its extreme upper position then only the upper part of the lifting cylinder will communicate with the upper part of the storage reservoir and thereby permit air to pass from theupper part of the lifting cylinder into the upper part of the storage chamber and thereby prevent the formation of a vacuum in the storage chamber as liquid is withdrawn therefrom and delivered into the lower part of the lifting cylinder. When however the lifting piston 27 reaches its uppermost position the lower end thereof is above the relief opening 83, thereby placing the interior of the lifting cylinder or chamber below the piston in communication with the storage chamber, whereby any pumping effect which is exerted by the operation of the pump, after the piston has reached its highest position, will exert no further lifting effect of the jack because the liquid at this time will merely by-pass from the lifting cylinder into the storage chamber and continue to circulate idly and thus prevent the apparatus from being strained unduly.

As a whole this lifting jack is very simple, sturdy and compact in construction, it is very effective in operation and the same contains no delicate parts which are liable to get out of order under rough usage.

I claim:

A lifting jack comprising a base having an opening, a bearing having a cup shaped body ar ranged in said opening, said cup shaped body having a laterally extending annular flange engaging the upper side of said base, an intermediate cylindrical portion projecting downwardly from said lateral flange and an inwardly turned downwardly tapering annular flange on the lower end of said intermediate portion, an elevating device adapted to engage the load to be lifted and having a downwardly projecting stem loosely fitting in said intermediate cylindrical portion of said body and engaging said inwardly turned flange thereof, and means for frictionally coupling said stem with said body including a split ring arranged in an annular groove on the periphery of said stem, the exposed portion of said ring being rounded and engaging the bore of said intermediate cylindrical portion.

JAMES N. MCLEAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,119,028 Schmidt et al May 31, 1938 2,153,845 Rosenberry Apr. 11, 1939 2,261,438 Harwood Nov. 4, 1941 2,283,593 Akins May 19, 1942 2,361,197 --Hallinan Oct. 24, 1944 2,412,414 Mueller Dec. 10, 1946 

